Contents. Introduction... xv

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1 Introduction... xv Welcome to IP Telephony Principles and Applications... xvi About This Course... xvii Unit 1 VoIP Services...1 Packet Telephony The Present: Separate Networks How Packet Telephony Works Making the Shift Packet Telephony Standards Internet Telephony Categories Computer-to-Computer Computer-to-Telephone Telephone-to-Telephone Web-to-Call Center Systems Telephony Gateway Dedicated Servers with Voice Cards Router or Access Concentrator with Voice Cards Packet Telephony Products Toll Bypass Products LAN-Based PBX Systems The UnPBX Voice Quality Encoding and Decoding Propagation Packetization Delay Jitter Packet Loss Voice Compression Activities Fundamental VoIP Network Components H.323 Network Components Terminals MCUs Gateways Gatekeepers iii

2 IP Telephony Principles and Applications iv MGCP MGCP Network Components Activities Factors Driving the Demand for Packet Telephony Long-Term Trends Open Standards, Open Market More Bandwidth Carrier Applications Enterprise Applications Voice Rides for Free Transparent Technology Improved Network Management Network Flexibility and Scalability Access to New Applications Activities Lesson 4 Private Virtual Private Networks...50 Private Communications Networks Cost Savings Improved Efficiency Enhanced User Satisfaction Activities Lesson 5 Public-Switched Telephone Network Remote Access Remote Access Applications Dial-Up Access ISDN Access ISDN Services DSL Services Physical Requirements ADSL Activities Unit 2 Enterprise Class IP Solutions Avaya Communication's Enterprise Class IP Solutions The Convergence Roadmap to E-Business Two Paths to Convergence IP PBX IP Telephony Combined IP-Enabled PBXs and IP Telephony Activities Avaya DEFINITY ECS Overall Connectivity DEFINITY ECS System Components Digital Networking PN

3 PPN EPN R300 Remote Office Communicator CSS SN ATM SN Main System Configurations PN Components TDM Bus Packet Bus Port Circuits Interface Circuits SPE DEFINITY Software Architecture Connecting with TCP/IP Networks LAN Gateway IP Trunking DEFINITY DCS Private Networks DCS Switch Components for DCS Networking Activities Avaya R300 Remote Office Communicator R300 Overview R300-Supported Devices Call Processing for R300 Station and Trunks R300 IP User Station Configurations IP Softphone IP Softphone Configurations Model 46xx IP Telephones Telephone Set Installation IP Telephone QoS Features DiffServ UDP Port Selection E911 Emergency Assistance Calls Activities Lesson 4 Avaya IP600 Internet Protocol Communications Server IP600 Overview IP600 Key Features and Characteristics Open Standards and Reliability Avaya Call Processing Software Built-In Gatekeeper with Embedded Gateway IP600 Hardware Hardware Hardware Components IP 600 Software Software Components Hairpinning and Shuffling Dynamic Jitter Buffers Causes of Jitter Activities v

4 IP Telephony Principles and Applications vi Lesson 5 Avaya Enterprise Directory Gateway Gateway Administration Overview DSMs Synchronization Engine LDAP Data Store Gateway Client Supported DEFINITY Objects Activities Unit 3 VoIP Network Quality of Service Techniques General QoS Concepts Types of Convergence Payload Protocol Physical Device Application Technology Organizational Network Requirements for Convergence Standards Converged Network Architecture A Hybrid Approach to Convergence Parallel WAN Paths for QoS Application-Level QoS The QoS Parameters Bandwidth Throughput Delay Jitter Packet Loss Availability Security Voice Quality Measurements Activities Admission Control and Traffic Shaping Traffic Shaping and Admission Control Admission Control Traffic Shaping Network Admission Policies Admission Control and Traffic Shaping Applications Activities Q VLAN Standard The Importance of a VLAN Standard The VLAN Tag Q as an Architecture

5 802.1Q Protocols The Promise of 802.1Q Activities Lesson p Traffic Prioritization Standard Priority Tags and Traffic Classes How 802.1p Prioritizes Traffic Mapping 802.1p Traffic Prioritization to IP and ATM Networks Activities Lesson 5 H.323 Standard for Packet Multimedia Overview of the H.323 Standard Version 1: Videophone Version 2: Packet-Based Multimedia Version 3: Under Development Other Standards of the H.323 Family The H.323 Protocols and Their Effect on Voice Stream QoS H.323 Protocols Audio Codecs Real-Time Transport Protocol (RTP) RTCP RAS: H Call Signaling: H Control Signaling: H H.323 Protocol Limitations Document Conferencing: T.120 Series Network Infrastructure Requirements Activities Lesson 6 Many Approaches to IP Network QoS Methods of Adding QoS to an IP Network CBQ CoS COPS DiffServ IntServ IP Precedence MPLS Policy Routing PQ RED RSVP ToS Traffic Shaping WFQ WRED Activities vii

6 IP Telephony Principles and Applications Lesson 7 APIs APIs That Support VoIP TAPI TSAPI JTAPI Comparing APIs Activities Unit 4 VoIP Network Integration with Legacy Services H.323 Call Processing H.323 Call Progression H.323 Call Progression Phases Gatekeeper Discovery and Registration: H.225 RAS Call Setup and Signaling: H Control Signaling: H Call Termination: H.245/H H.323v2 faststart SIP Activities SS7 Integration SS7 Integrated Services SS7 Architecture Service Switching Point (SSP) Signal Transfer Point (STP) Service Control Point (SCP) SS7 Network Links SS7 Call Signaling Steps LNP SS7 Protocol Stack Adding SS7 to VoIP SS7 to ITSP Call Progression Activities ISDN ISDN Protocols Data Link Layer Call Setup, LAPD Network Layer Call Control, I Network Layer Packet-Switching, X ISDN Signaling DSS PSS QSIG and ISDN Supplementary Services ISDN CPE Supported Switch Types ISDN/VoIP Integration Activities viii

7 Lesson 4 Frame Relay What is Frame Relay? Frame Relay Terms PVCs Frame Relay Operation Frame Relay Frame Information Field Frame Relay Header Field Flow Control Congestion Management Frames Frame Relay Addressing Interconnecting LANs Using Frame Relay Frame Relay Implementation Options Private Frame Relay Public Frame Relay Hybrid Frame Relay End-User Access to Frame Relay Networks Frame Relay vs. Private Line Networking Frame Relay Services Public Frame Relay Services VoFR Services Bandwidth on Demand Conditional Bursting Cost Considerations Carrier Choice Considerations CIR Congestion Control Reports and Statistics Frame Relay Network Requirements Activities Lesson 5 ATM The Need for ATM Transfer Modes STM PTM ATM Connection-Oriented Mode ATM Network Interfaces Fixed-Length Data Cells Header Details B-ISDN and ATM AAL ATM Layer Physical Layer The Leaky Bucket Analogy Activities ix

8 IP Telephony Principles and Applications Lesson 6 Fax Services How Internet Faxing Works Types of FoIP Services ITU-T T-Series Recommendations Activities Unit 5 VoIP Network Engineering, Management, and Support Telecommunications Traffic Engineering Carried Load Conversation Time Operating Time Holding Time Constant Distribution Exponential Distribution Probability Grade of Service Trunk Usage CCS Erlang The Erlang B Traffic Formula Erlang C and Poisson Tables Poisson: Immediate Redial Erlang C: Infinite Queue No Formula Is Perfect Estimating Total System Capacity Outbound Trunk Capacity Tie Trunks VoIP Link Capacity PBX Processing Capacity Adjusting To Changes Activities Converged Network Design and Traffic Engineering Converged Network Traffic Engineering Where Do We Begin? The Network Design Process Phase 1: Requirements Gathering Phase 2: Analysis of the Existing Network Phase 3: Logical Design Phase 4: Physical Design Phase 5: Installation and Maintenance Activities Security Security Threats Layered Approach to a Comprehensive Security Solution Security Policy x

9 User Awareness Training Acceptable Use Agreement Monitoring Enforcement Physical Security Encryption Key Size and Encryption Strength Legal Issues in Cryptography Commonly Used Encryption Systems DES Clipper Chip Kerberos SSL PGP Access Control User Authentication Passwords Smart Cards Digital Certificates Biometric Authentication Message Digests and Digital Signatures Firewalls Network Layer Firewalls Application Firewalls Hybrid Firewalls Firewall Rules Private IP Addresses/Network Address Translation IPSec AH ESP Implementing IPSec Security Management Voice Service Specific Vulnerabilities Remote Access Service Toll Fraud Activities Lesson 4 Managing Service Levels What is an SLA, and Why is it Important? Why are Enterprise Network Users Demanding SLAs? VoIP SLAs Service Level Measurements Measuring An SLA SNMP Architecture Service Measurement Approaches The Provider s Viewpoint SNMP Polling Using SNMP and RMON to Measure Performance How RMON Works RMON Extensions to SNMP Converged Network Performance MIBs DiffServ MIB IntServ MIB xi

10 IP Telephony Principles and Applications xii Active Network Probing Ping Traceroute Paired Probes Service Measurement Approaches The Customer s Viewpoint Activities Lesson 5 Converged Network Failure Points Potential Network Failure Points Converged Network To PSTN Interface The LAN Protocol Overhead Actual Codec Bandwidth Required The Effect of Protocol Overhead on VoIP Networks IP Multicast Traffic Network Performance The WAN Activities Lesson 6 A Converged Network Troubleshooting Example Network Troubleshooting Steps Identify the Exact Issue Re-create the Problem Isolate the Cause Formulate and Implement a Correction Test the Solution Document the Problem and Solution and Provide Feedback Troubleshooting Methods A Network Problem Example Digging Deeper The Fix Activities Unit 6 Future Technologies Supporting Convergence Internet Protocol version 6 (IPv6) IP Next Generation Expanded Addresses Multimedia Ready Multicast Support Bandwidth Reservations Packet Prioritization Jumbograms Plug and Play Address Discovery Network Information Discovery Automated Address Changes Support for Mobile Hosts Dead Neighbor Detection Increased Efficiency

11 Added Flexibility Configurability of Features IPv4 Compatibility Security Infrastructure Encryption Authentication IPv6 Header Format Activities WLANs Equipment and Operating Modes The Physical Layer FHSS DSSS The Data Link Layer The Near/Far Problem The Hidden Node Problem Error Correction and Reduction Enhancements to the PHY Layer b a No Common Ground Activities Mobile IP Mobile IP Mobile IP Enables Roaming Data Services Mobile IP Network Components How a Mobile Node Connects to the Home Network Directly Attached to the Home Network Attached to a Foreign Network Mobile IP Security Mobile IP Deployment Mobile IP over Cellular Activities Course Quiz References Reference Books Technical Manuals Magazines Internet Sources RFCs Glossary Index xiii